DNR: Wisconsin frack sand sludge spill nontoxic

Wisconsin officials say early tests have found no harmful chemicals after a spill near a frack sand mine sent millions of gallons of sludge into waterways.

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A contactor's bulldozer slid into a pond last month, leading to an hourslong rescue at the Hi-Crush mine in the western Wisconsin town of Whitehall. Rescuers emptied 10 million gallons (38 million liters) of water to reach the driver. The spill sent thick sludge into a Trempealeau River tributary, tinting waterways orange as the thick plume traveled downstream and into the Mississippi River.